This is an epidemiological study of the effects of prenatal marijuana consumption on offspring. It represents a unique opportunity to explore this relationship in a cohort of women and their children who currently are being studied during pregnancy and through the eighth postpartum month. We propose to extend the study to assess the children at 18 months and 3 years of age. Growth parameters, morphological characteristics and neurological status will be assessed at each time point. Developmental status and behavioral characteristics will be measured using age-appropriate instruments. This study will: (1) Assess the effects of maternal marijuana use during pregnancy on the long-term physical development and morphological characteristics of children. (2) Examine the developmental status and behavioral characteristics of these children at 18 months and 3 years. (3) Determine differences in electroencephalographic patterns and sleep organization in these children. Careful assessment of sociodemographic characteristics, life style, other drug use and psychiatric symptom levels allows us to separate the direct teratogenic effect of marijuana use from the contributing effects of other factors that accompany marijuana use. Instruments and procedures from the prenatal periods through the eight-month postpartum assessment have been developed, tested and implemented.